20,166 research outputs found
Climate Change Mitigation Policies: Aggregate and Distributional Effects
We evaluate the aggregate and distributional effects of climate change mitigation policies using a multi-sector equilibrium model with intersectoral input–output linkages and worker heterogeneity calibrated to different countries. The introduction of carbon taxes leads to changes in relative prices and inputs reallocation, including labor. For the United States, reaching its original Paris Agreement pledge would imply at most a 0.6% drop in output. This impact is distributed asymmetrically across sectors and individuals. In the US, workers with a comparative advantage in dirty energy sectors who do not reallocate suffer a welfare loss 12 times higher than workers in non-dirty sectors, but constitute less than 1% of the labor force
Comunicação corporativa na era da televisão digital interativa.
Este artigo aborda a pesquisa que está sendo conduzida na empresa sobre o desenvolvimento de tecnologias e metodologias de produção de conteúdo para a TV digital, que visa criar um canal para divulgação científica e transferência de tecnologia cujo foco é amparado em um novo paradigma baseado no potencial das novas mídias para a democratização e a inclusão social de produtores rurais. Os estudos incluem o desenvolvimento de um ambiente interativo e a produção de conteúdos-piloto audiovisuais, envolvendo a participação da comunidade, tanto durante o processo construtivo quanto na validação das metodologias criadas, num processo interativo mediado pelas tecnologias multimídia
Comparison of total variation algorithms for electrical impedance tomography
The applications of total variation (TV) algorithms for electrical impedance tomography (EIT) have been investigated. The use of the TV regularisation technique helps to preserve discontinuities in reconstruction, such as the boundaries of perturbations and sharp changes in conductivity, which are unintentionally smoothed by traditional l2 norm regularisation. However, the non-differentiability of TV regularisation has led to the use of different algorithms. Recent advances in TV algorithms such as the primal dual interior point method (PDIPM), the linearised alternating direction method of multipliers (LADMM) and the spilt Bregman (SB) method have all been demonstrated successful EIT applications, but no direct comparison of the techniques has been made. Their noise performance, spatial resolution and convergence rate applied to time difference EIT were studied in simulations on 2D cylindrical meshes with different noise levels, 2D cylindrical tank and 3D anatomically head-shaped phantoms containing vegetable material with complex conductivity. LADMM had the fastest calculation speed but worst resolution due to the exclusion of the second-derivative; PDIPM reconstructed the sharpest change in conductivity but with lower contrast than SB; SB had a faster convergence rate than PDIPM and the lowest image errors
Efeito da percentagem de grãos gessados sobre a viscosidade do arroz.
O objetivo deste trabalho foi avaliar a viscosidade do arroz com diferentes porcentagens de grãos gessados, sob efeito da temperatura e tempo
Pressure tuning of structure, superconductivity and novel magnetic order in the Ce-underdoped electron-doped cuprate T'-Pr_1.3-xLa_0.7Ce_xCuO_4 (x = 0.1)
High-pressure neutron powder diffraction, muon-spin rotation and
magnetization studies of the structural, magnetic and the superconducting
properties of the Ce-underdoped superconducting (SC) electron-doped cuprate
system T'-Pr_1.3-xLa_0.7Ce_xCuO_4 with x = 0.1 are reported. A strong reduction
of the lattice constants a and c is observed under pressure. However, no
indication of any pressure induced phase transition from T' to T structure is
observed up to the maximum applied pressure of p = 11 GPa. Large and non-linear
increase of the short-range magnetic order temperature T_so in
T'-Pr_1.3-xLa_0.7Ce_xCuO_4 (x = 0.1) was observed under pressure.
Simultaneously pressure causes a non-linear decrease of the SC transition
temperature T_c. All these experiments establish the short-range magnetic order
as an intrinsic and a new competing phase in SC T'-Pr_1.2La_0.7Ce_0.1CuO_4. The
observed pressure effects may be interpreted in terms of the improved nesting
conditions through the reduction of the in-plane and out-of-plane lattice
constants upon hydrostatic pressure.Comment: 11 pages, 10 figure
Biomassa seca e relação raiz-parte aérea de acessos de paspalum submetidos ao alagamento do solo.
In general, tropical pastures have limitations of use under conditions of stress by flooding. The purpose was to measure the flooding stress response in dry biomass and root/shoot ratio of five accessions of Paspalum (Paspalum regnellii, BRA 23469, BRA 23540, BRA 23671 and 21377 BRA) and Brachiaria brizantha cv. Marandu at the end of the stress period and after recovery under ideal water conditions. The greater shoot biomass was observed in Brachiaria brizantha, being similar among Paspalum accessions. The root biomass and the root/shoot were negatively affected by flooding and also by the collection period at the end of 28 days of stress. Flooding considerably influenced biomass allocation to roots and root/shoot ratio Paspalum genotypes. The allocation model is important for understanding the strategies adopted by these plants to acquire competitive advantages under water stress
Laser Cooling of Trapped Fermi Gases deeply below the Fermi Temperature
We study the collective Raman cooling of a polarized trapped Fermi gas in the
Festina Lente regime, when the heating effects associated with photon
reabsorptions are suppressed. We predict that by adjusting the spontaneous
Raman emission rates and using appropriately designed anharmonic traps,
temperatures of the order of 2.7% of the Fermi temperature can be achieved in
3D.Comment: 4 pages, 3 figures; final versio
Anharmonicity in one-dimensional electron-phonon system
We investigate the effect of anharmonicity on the one-dimensional half-filled
Holstein model by using the determinant quantum Monte Carlo method. By
calculating the order parameters we find that with and without anharmonicity
there is always an transition from a disorder phase to a dimerized phase.
Moreover, in the dimerized phase a lattice dimerization and a charge density
wave coexist. The anharmonicity represented by the quartic term suppresses the
dimerization as well as the charge density wave, while a double-well potential
favors the dimerization. In addition, by calculating the correlation exponents
we show that the disorder phase is metallic with gapless charge excitations and
gapful spin excitations while in the dimerized phase both excitations are
gapful.Comment: 5 page
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